Extract split_on_commas into a utils module
Promote top level args to put-metric-data
Rename renames test to utils
Add util code for validating mutex groups
Add comment about default value

As per review feedback.
Merge branch 'put-metric-data' into develop

* put-metric-data:
  Add comment about default value
  Add util code for validating mutex groups
  Rename renames test to utils
  Promote top level args to put-metric-data
  Extract split_on_commas into a utils module